crypto.java

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.InvalidAlgorithmParameterException;
import java.security.spec.AlgorithmParameterSpec;
import android.util.Base64;

// 출처: https://niceman.tistory.com/91
//
// * AES/CBC 암호화/복호화
//   안드로이드와 C++ 간에 호환성을 맞춤
//
// * 자바에서 AES/CBC 사용법
//   public static String secretKey = "비밀키";
//   AES256Chiper.AES_Encode("암호화 내용");
//   AES256Chiper.AES_Decode("복호화 내용");
//
// * C++에서 AES/CBC 사용법
//   std::string secret = "비밀키";
//   std::vector<uint8_t> key(secret.begin(), secret.end()), iv(Scrypt::defaultBlockSize());
//   std::string encrypted = Scrypt::encrypt("암호화 내용", key, iv);
//   std::string decrypted = Scrypt::decrypt("복호화 내용", key, iv);
//
public class AES256Chiper {

    public static byte[] ivBytes = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
    public static String secretKey = "비밀키";

    //AES256 암호화
    public static String AES_Encode(String str)	throws java.io.UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException,	IllegalBlockSizeException, BadPaddingException {

        byte[] textBytes = str.getBytes("UTF-8");
        AlgorithmParameterSpec ivSpec = new IvParameterSpec(ivBytes);
        SecretKeySpec newKey = new SecretKeySpec(secretKey.getBytes("UTF-8"), "AES");
        Cipher cipher = null;
        cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, newKey, ivSpec);

        return Base64.encodeToString(cipher.doFinal(textBytes), 0);
    }

    //AES256 복호화
    public static String AES_Decode(String str)	throws java.io.UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {

        byte[] textBytes =Base64.decode(str,0);
        //byte[] textBytes = str.getBytes("UTF-8");
        AlgorithmParameterSpec ivSpec = new IvParameterSpec(ivBytes);
        SecretKeySpec newKey = new SecretKeySpec(secretKey.getBytes("UTF-8"), "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, newKey, ivSpec);
        return new String(cipher.doFinal(textBytes), "UTF-8");
    }
}